When i Start Steam Offline, will it minimize the risk of a VAC Ban? I'll use the Trainer only for SP of course (Unlocking Chars etc.).Keep goin' CH-Team!

Yes and No, VAC is a DLL part of the game so it'll be there even when you play in offline mode or play online, but VAC only activates if told to, so like if you play CSGO and join a server with VAC disabled it won't activate. Once when doing multiplayer cheats people would try to disable it and/or stop it from activating but Valve now detects that and will kick you out if it ain't detected running.. what my long message is supposed to say, if solo is specifically set to not have VAC which it 99% should be if you can use it while not being connected to the internet because it doesn't keep logs it uploads the data while you are playing not after.

EDIT: Keep in mind very little is known of VAC3 which is why I said 99%!